The invention relates to a wheel suspension for automotive vehicles, with at least one wheel control member and with the wheel suspension system comprising a coil spring and at least one vehicle component arranged in the surrounding area of the coil spring.
In wheel suspensions of this type, the space is frequently very restricted. However, in most cases a quite specific arrangement is desirble for the individual parts of the wheel suspension, for functional reasons. This oftentimes forces compromises in conjunction with the other constructional conditions resulting from the design of the vehicle.
Thus, for example, French Pat. No. 1,573,273 concerns a wheel suspension of this general type wherein the coil spring is in the way of the axle shaft and is therefore supported on the wheel control member by way of a special bracket bridging the axle shaft. Consequently, this construction requires a special bridging member, the manufacture and mounting of which cause additional expenses.
In another conventional wheel suspension, German Published Unexamined Application (DOS) No. 2,431,675, the coil spring of the spring leg is to be supported on the damper thereof above the vehicle wheel. This structural solution, however, requires a large construction height of the spring leg, counteracting, for example in case of front axles, the tendency of placing the contours of the engine hood increasingly lower.
Thus, a great variety of compromises have been made, namely in constructional as well as functional viewpoints (for example with respect to spring ratio), wherein corresponding problems are encountered precisely in connection with the arrangement of coil springs because these require a large amount of space.
Special difficulties evolve, of course, if an already designed vehicle is to be retrofitted, for example from rear wheel drive to front wheel drive or four wheel drive, or is to be equipped with coil springs of a different size for roadway and terrain.
Therefore, an object of the invention is to provide a wheel suspension of the type discussed hereinabove which permits a construction adaptable to a great variety of different requirements in an especially advantageous way.
This object is achieved by the invention by configuring the coil spring so that the vehicle component extends between turn sections of the coil spring, inside the envelope or axial projection of the adjacent outer circumference of the coils of the spring.
In the wheel suspension of this invention, the coil spring is accordingly expanded and extended past the area of a spring turn at the location where it would otherwise be in the way of a vehicle part to be arranged in its surrounding area. In advantageous preferred embodiments, the vehicle part is arranged with a partial section thereof within the projection of the spring coil circumference. In other preferred embodiments the vehicle part is arranged with its total cross section contained within the widened area of the spring. Preferred embodiments are comtemplated where the vehicle part completely penetrates through the coil spring and advantageously intersects the axis of the coil spring.
The extent of expansion of the spring is to be selected so that the turn portions looping around the respective vehicle component and pertaining to the spring turn which, as compared with the regular spring lead, is designed with a larger lead and/or is expanded, are at a lateral distance from the vehicle component ensuring that any contact between the spring turn portions and the vehicle component or components is excluded at the maximally possible spring stroke. In this connection, the coil spring can be arranged to be upright or in a horizontal position.
The term "regular lead of the coil spring" is to be understood to mean that either all spring turns of the coil spring have the same mutual spacing from turn to turn over the entire length of the spring, or that the lead between individual groups of spring turns is also changed in a predetermined manner over the length of the coil spring. Moreover, the coil spring can be fashioned according to preferred embodiments to be of a circular-cylindrical, truncated cone, barrel shape or as a spring with a reduced cross section.
The vehicle component can be any part to be accomodated in the region of a wheel suspension, and thus can be, for example, a part of the wheel control system, e.g. a strut or a control arm or, one or several pipelines, for example, exhaust pipes, an axle shaft, a body part, or a wheel.
Furthermore, various vehicle components can simultaneously be in engagement with the widened portion of the spring, or can pass entirely therethrough.
In certain preferred embodiments, the coil spring is constructed with only one spring turn at one end of the spring having the larger lead and a plurality of spring turns at the other end thereof. In the same way, spring turns can be arranged on both sides of the widened portion of the spring in an identical or in a different number. Thus, the zone of the coil spring exhibiting the spring expansion can be changed according to the invention, in dependence on the spatial correlation of the coil spring and the vehicle component(s).
In this connection, the structure of the coil spring offers an important advantage, according to certain embodiments, especially if the spring supporting surfaces assume an oblique mutual positioning during compression or lenghtening of the coil spring. In such a case, it is ensured that the coil spring can no longer be deformed (bulge) to an intolerable extent transversely to its longitudinal axis. In this connection, advantageous embodiments include coil springs designed with different flexural resilience or spring constant for the spring turns at the side of the vehicle component being circumvented.
Another advantageous embodiment of the invention includes an arrangement where the turn diameter of the spring turns, adjoining on both sides of the spring turn exhibiting the larger leads, are different from one another. This construction of the spring is advantageous if, for example, the installation space for arranging the coil spring is correspondingly restricted, and yet it is to ensured that the coil spring cannot be deformed unduly transversely to its longitudinal axis.
Furthermore, in view of the objectives of the invention, it is advantageous according to certain embodiments to select the wire diameter of the spring turns adjoining on both sides the spring turn with the larger lead to be differently large and/or to reduce, at least at one of the spring sections adjoining the widening of the spring, the diameter of the individual spring turns from one turn to the next in the direction of the supporting surface of this spring section.
Further objects, features, and advantages of the present invention will become more apparent from the following description when taken with the accompanying drawings which show, for purposes of illustration only, embodiments in accordance with the present invention.